Companion object that facilitates the importing of AsyncAssertions members as
an alternative to mixing in the trait. One use case is to import AsyncAssertions's members so you can use
them in the Scala interpreter.

Scales the passed Span by the Double factor returned
by spanScaleFactor.

Scales the passed Span by the Double factor returned
by spanScaleFactor.

The Span is scaled by invoking its scaledBy method,
thus this method has the same behavior:
The value returned by spanScaleFactor can be any positive number or zero,
including a fractional number. A number greater than one will scale the Span
up to a larger value. A fractional number will scale it down to a smaller value. A
factor of 1.0 will cause the exact same Span to be returned. A
factor of zero will cause Span.ZeroLength to be returned.
If overflow occurs, Span.Max will be returned. If underflow occurs,
Span.ZeroLength will be returned.